There is known a technology for generating a virtual avatar on the basis of a visual image obtained by imaging a driver and estimating how a mirror would be seen in the eyes of the virtual avatar (see FIGS. 9 and 10 of Japanese Patent Application Publication No. 2013-14310 (JP 2013-14310 A)). In JP 2013-14310 A, the mirror is rotated such that the proportion between an upper portion and a lower portion with respect to a virtual horizontal line that appears on the mirror etc. is optimum. According to the technology, the mirror can be rotated in a direction that is suitable for the posture of the driver.